Tableau api 根据最新日期获取数据

根据下面的数据集，我试图根据最新的报告日期获取最新的成本

例如：当报告日期=预测日期（列标题）时，选择该报告日期的值，该值可通过此公式实现

IF [Report Date]=[Forecast Date] THEN [Forecasted Cost] END

但我还希望获得截至最新报告日期（即2019年2月15日）的后续值。我如何做到这一点

所需输出

+------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+
|            | 8/15/2018 | 9/15/2018 | 10/15/2018 | 11/15/2018 | 12/15/2018 | 1/15/2019 | 2/15/2019 | 3/15/2019 | 4/15/2019 | 5/15/2019 | 6/15/2019 | 7/15/2019 | 8/15/2019 |
+------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+
| Final Cost |  646.00   |  646.00   |  620.00    |  620.00    |  550.00    |  445.00   |  361.00   |  332.50   |  315.40   |  296.40   |  290.70   |  285.00   |  279.30   |
+------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+   

+------+-------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+
| Item | Report Date | 8/15/2018 | 9/15/2018 | 10/15/2018 | 11/15/2018 | 12/15/2018 | 1/15/2019 | 2/15/2019 | 3/15/2019 | 4/15/2019 | 5/15/2019 | 6/15/2019 | 7/15/2019 | 8/15/2019 |
+------+-------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+
| 4124 | 8/15/2018   |  646.00   |  646.00   |  658.00    |  658.00    |  658.00    |  658.00   |  658.00   |           |           |           |           |           |           |
| 4124 | 9/15/2018   |           | 646       | 626        | 626        | 626        | 622       | 622       | 622       |           |           |           |           |           |
| 4124 | 10/15/2018  |           |           | 620        | 620        | 620        | 585       | 585       | 585       | 555       |           |           |           |           |
| 4124 | 11/15/2018  |           |           |            | 620        | 620        | 610       | 595       | 554.5     | 543.38    | 535.35    |           |           |           |
| 4124 | 12/15/2018  |           |           |            |            | 550        | 535       | 505       | 490       | 490       | 490       | 490       |           |           |
| 4124 | 1/15/2019   |           |           |            |            |            | 445       | 430       | 420       | 410       | 400       | 390       |       384 |           |
| 4124 | 2/15/2019   |           |           |            |            |            |           | 361       | 332.5     | 315.4     | 296.4     | 290.7     |       285 | 279.3     |
+------+-------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+

数据集

+------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+
|            | 8/15/2018 | 9/15/2018 | 10/15/2018 | 11/15/2018 | 12/15/2018 | 1/15/2019 | 2/15/2019 | 3/15/2019 | 4/15/2019 | 5/15/2019 | 6/15/2019 | 7/15/2019 | 8/15/2019 |
+------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+
| Final Cost |  646.00   |  646.00   |  620.00    |  620.00    |  550.00    |  445.00   |  361.00   |  332.50   |  315.40   |  296.40   |  290.70   |  285.00   |  279.30   |
+------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+   

+------+-------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+
| Item | Report Date | 8/15/2018 | 9/15/2018 | 10/15/2018 | 11/15/2018 | 12/15/2018 | 1/15/2019 | 2/15/2019 | 3/15/2019 | 4/15/2019 | 5/15/2019 | 6/15/2019 | 7/15/2019 | 8/15/2019 |
+------+-------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+
| 4124 | 8/15/2018   |  646.00   |  646.00   |  658.00    |  658.00    |  658.00    |  658.00   |  658.00   |           |           |           |           |           |           |
| 4124 | 9/15/2018   |           | 646       | 626        | 626        | 626        | 622       | 622       | 622       |           |           |           |           |           |
| 4124 | 10/15/2018  |           |           | 620        | 620        | 620        | 585       | 585       | 585       | 555       |           |           |           |           |
| 4124 | 11/15/2018  |           |           |            | 620        | 620        | 610       | 595       | 554.5     | 543.38    | 535.35    |           |           |           |
| 4124 | 12/15/2018  |           |           |            |            | 550        | 535       | 505       | 490       | 490       | 490       | 490       |           |           |
| 4124 | 1/15/2019   |           |           |            |            |            | 445       | 430       | 420       | 410       | 400       | 390       |       384 |           |
| 4124 | 2/15/2019   |           |           |            |            |            |           | 361       | 332.5     | 315.4     | 296.4     | 290.7     |       285 | 279.3     |
+------+-------------+-----------+-----------+------------+------------+------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+

---

首先，您需要转换数据集，即有4列“项目”、“报告日期”、“预测日期”和“预测成本”。然后创建一个过滤器“forecast date>=report date”，并按forecast date显示值。 现在，每个预测日期都有多个值。如果您只想获取最新的值，则可以使用表格计算窗口（日期差异）。

“透视”，而不是转置